The invention relates generally to internal combustion engines and, more particularly, to two stroke internal combustion engines in which each cylinder has associated therewith a separate individual crankcase.
In the past, such separate crankcases have been sealed against loss of pressure by preventing fluid flow from the crankcases and between the crankshaft and the engine block and crankcase cover by use of a single sealing member between a crankshift disc and a cylindrical surface formed by the engine block and by a crankcase cover. In practice, the engine block and crankcase cover were manufactured with relatively tight tolerances and the engine block and crankcase covers were individually selected for marriage with each other to produce, as nearly as practical as possible, an annular concentric cylindrical sealing surface adapted to cooperate with a single sealing member carried in a groove on the crankcase disc.
As a result of tight tolerances, and the practical requirement for matching or marrying engine blocks and crankcase covers to obtain as nearly as possible a truly geometric cylindrical sealing surface, the past practice has been excessively expensive.
Attention is also directed to the following United States Patents:
______________________________________ 2,885,249 Payne May 5, 1959 2,356,377 Voitik December 5, 1967 3,455,565 Jepsen July 15, 1969 4,615,531 Green October 7, 1986 ______________________________________